Middlings-purifier.



No. 689,257. Patented Dec. 17, l90l G. WALTER. 'mnnuuas PURIFIEB.

(Application filed June 25, 1900.)

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No. 689,257. I

Patented Dec. 17, l90l. G. WALTER.

MIDDLINGS PURIFIER.

(Apphcntxon filed June 25, 1900 (No Model-7 s SheetsShq at 2.

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UNITED STATES:

PATENT @FFICE.

GEORGE l/VALTER, OF MARYSVILLE, KANSAS.

MIDDLINGS-PURIFIER.

SPECIFICATION forming part of Letters Patent No. 689,257, dated December17, 1901. Application filed June 25, 1900. Serial No. 21,448. (Nomodel.)

sas, have invented certain new and useful Improvements inMiddlings-Purificrs, of which the following is a specification.

The invention relates to middlings-purifiers.

The object of the invention is to provide a machine whereinmiddlings-stock may be placed and the dust, bran, and coarse materialseparated therefrom.

A further object is to provide means for separating the fine floatingdust from the heavier coarser particles after the same has been takenout of the middlings-stock.

A further object is to provide a purifier wherein difierent grades ofstock may be cleaned simultaneously without mixing.

A further object is to provide a machine that is easily operated, oflarge capacity, and one that will quickly and efiectually clean themiddlings of all impurities.

The invention consists generally in a swinging or gyrating casingdivided by partitions into compartments or chambers and radialair-trunks through which and said compartments ascending currents of airmay be maintained.

Further, theinvention consists in improved means for regulating thecurrents of air through said compartments.

Further, theinvention consistsin improved means for feeding ordelivering the middlings' stock upon the sieves. 2

Further, the invention consists in providing means for preventing themeshes of the sieves from clogging.

Further, the invention consists in various constructions andcombinations, all as hereinafter described, and particularly pointed outin the claims.

In the accompanying drawings, forming part of this specification, Figure1 is a vertical section on the line w x of Fig. 2. Fig. 2 is ahorizontal section on the line 1 3 of Fig. 1. Fig. 3 is a similar viewon the line 2' z of Fig. 1. Fig. 4 is a horizontal section on the lineto 11) of Fig. 1. Fig. 5 is a detail shoving the manner of supportingthe sieves in the purifier-casing, and Figs. 6 and 7 are details of thesieves.

of the casing through a large opening 7 and with openings 8 atintervalsin the floor 3 by short'air-trunks 9. A shaft 10 extendsvertically through said fan-casing and is provided at its upper end'with a pulley 11 and belt 12, that is connected to a suitable source ofpower. A sleeve 13 is arranged on said shaft and'provided with a pulley14, over which passes a belt 15. Afan 16 is arranged on said sleevewithin the fan-casing, and said sleeve being loose on the shaft permitsthe fan to be driven at a higher speed than the shaft from which thepurifier is operated.

The frame of the machine on one side extends above the floor 3 and isprovided with a brace 17 near the upper end of said shaft to support andstay the same against lateral movement. A bearing-block 18 is providedon the fioor 3 near the lower end of the shaft 10, and said shaft isadapted to extend down through said floor and is provided at its lowerend with a heavy counterbalance-wheel 19, on which a shaft 20 iseccentrically mounted.

21 represents the casing of the swinging or gyrating purifier. Thiscasing may be either round or polygonal, as preferred, and is preferablyprovided with a central stud or hub 22,having a longitudinal opening 23to receive the metal tube 23,and a shaft 20, which passes throughjournal-boxes 24 provided at the top and bottom of the casing, as shownin Fig. 1. The lower end of the shaft 20 extends below the journal orbearing box 24 and is preferably mounted in a counterbalance-wheelcorresponding to the one heretofore described and which is in turneccentrically mounted on a short stud 25, mounted in bearings 26 on across-bar at the bottom of the frame 2.

The interior of the casing 21 is divided by vertical partitions 27 intoa series of independent compartments 28, and, as shown in Figs. 2 and 3,I prefer to provide six of these compartments, though there may be agreater or less number, according to the diameter of the casing and thesize of the sieves to be used. When a circular form of casing is used,the sieve-frames are triangular in form, corresponding to a sector of acircle; but if the casing is polygonal in form the sieve-frames may beof any desired shape to adapt them to the compartments in which they areused.

29 represents one of the sieve-frames, which is preferably provided withslots 30 in its sides to receive ribs 31 on the partition-wall andwhereon the frame is slidable. There may be any desired number of sievesin each compartment according to the height of the machine and thecondition of the material to be cleaned; but in the drawings I haveshown the purifier provided with four sieves in each compartment. At theouter ends of the sieves are removable panels 32, that are normally heldin place by bolts 33 and thumb-screws 34. The sieve-frames beingslidable on their supports within the compartments may be easily andquickly taken out or inserted by removing these panels. This.construction permits any of the sieves to be removed for the purpose ofcleaning or repairing the same or for substituting those of differentmesh or when it is desired to operate the machine with a less number.Each sieve is preferably composed of a series of narrow strips of silkcloth or other suitable sieve material 29', preferably four or fiveinches in width, arranged transversely in the frames, and these stripsmay be of different degrees of mesh according to the material to bepassed through them, the outer strips being finer, preferably, thanthose near the center of the machine. (See Fig. 3.) Between these narrowstrips I prefer to arrange at an incline a series of narrowcomparatively stiff strips or tapes 37, extending transversely of thesieves'and forming, with the edges of the sieve-strips, ribs orprojections which serve to advance the material toward the in ner endsof the sieves. These projections will also serve to prevent the materialfrom dancing around on the sieves and will cause it tospread out in evensheets and advance uniformly over the same. The number of sieves used ineach compartment will depend largely upon the condition of the materialto be cleaned. In coarse middlings the difference in weight between dustand bran and the purified stock is greater than in fine middlings.Consequently a larger number of sieves may be employed in thosecompartments used for cleaning coarse than for those for cleaning finemiddlings. In fine middlings the weight of the dust and purifiedstock'is nearly the same. ThereforeI prefer to provide a larger spacebetween the sieves and the perforated plates in the compartments usedfor cleaning fine middlings to allow room for the middlings to settleand prevent their being carried away by the air-current. I am thus ableto effect a very complete separation of any grade of stock.

I prefer to provide a series of steps or serrations 38 in the sides anda portion of the ter of the machine.

outer ends of the sieve-frames, and between said stepsand the middleportion of the sieves I provide ribs 39, having openings 40 betweentheir inner ends,communicatingwith the passage-ways formed by said'ribsinrthe partition-walls. I prefer to extend the ribs around the ends ofthe frames, leaving openings through which the cleaning material maypass onto the sieves. When the stock is fed into the machine, a quantityof corn, beans,wheat, or similar material is mixed with it and, fallingupon the sieves, cleans the meshes of the same as the stock is advancedtoward the cen- As the machine is operated the corn, beans, or likematerial collects at the inner ends of the sieves and enters thepassages formed by the ribs 39 and the partition-walls and is advancedby the corrugated floors of the same back to the outer or receiving endsof the sieves, where it is discharged onto the meshes of the sievesagain and is moved over the same as before. The corn or beans beingheavier than the middlings stock will lieclose to the meshes of thesieves and will thoroughly clean the same and will be kept in motionback and forth over the sieves as the machine is gyrated. The sieves arethus easily cleaned and prevented from clogging without the necessity ofremoving them and without any delay in the operation of the machine.

Above each sieve, near the outer end of the same, I prefer to provide areceiving-chamber or feed-receptacle 41, provided in its floor with aseries of discharge-slots 42 and overflow openings or slots 43 in itsouter wall. These feed chambers or receptacles extend, preferably,across the sieves and receive the middlings-stock from feed spoutslocated above them. The upper feed-spout 43 of the series extends upthrough a plate 44, provided with slots 45, and through the top of thecasing'and communicates with a spout 46 and a hopper 47,provided on thefloor 3 and adapted to receive the middlings-stock'from a delivery orfeed pipe 48. As the material flows down into the receiving-chamber itfalls through the slots 42 upon the outer ends of the sieves and isadvanced over the same by the motion of the machine, and saidchamberextending entirely across the sieves insures the evendistribution of the material thereon. If the holes in the floor of thefeed-chamber become clogged and the chamber fills up with the middlingsstock, the surplus material will be discharged through theoverflow-slots 43, provided in the wall of the chamber, and will fallupon the head of the sieve beneath and mingle with the material thatfalls through the holes or slots 42.

In each compartment beneath the upper sieve of the series I prefer toprovide gathering-boards 49, that project beyond the panels at the outerends of the sieves and are provided with curved strips 50, arranged topartially close the openings 51 between said boards and the panelsimmediately above the be one for each compartment.

same. These openings 51 form passages through which air is admitted tothe space beneath the sieves. Beneath each gatheringboard are platescorresponding to the plate 44, heretofore described, having slots 45,through which the dust and other foreign material gathered up by theair-currents are lifted and conveyed to the air-trunks hereinafterdescribed.

Beneath each sieve of the series I prefer to provide a vertical spout52, having its upper end flush with the top of the gathering-board andsupported thereby and its lower end fitting Within an opening in the topof the receiving-chamber and adapted to convey the material thereto. Theconstruction and alternate arrangement of the sieves, gatheringboards,and perforated floors are carried out from the top to the bottom of thecasing, at which latter point a discharge-opening 53 is provided beneaththe lower sieve of the series communicating with a discharge-spout 54.

The air-trunks which I have provided in this machine for receiving thedust and other foreign material separated from the middlings by theair-currents are preferably radial in form, are designated byreference-figures 55, and are arranged between the alternate pairs ofcompartments, so that there is a dust-collecting chamber or air-trunkfor each pair of compartments. The side walls of these air trunks areprovided with a series of horizon tal slots or openings 56, arranged atintervals therein, each slot or opening communicating with the spaceabove the slotted plates in the adjoining compartment. Upon thepartitionwalls at the ends of the slots I provide slats or bars 57,forming guides for the short slats 58, that are adapted to slide betweenthem over the openings 56. The slats 58 are preferably connected by abar 58, provided with short slots 59 to receive bolts 60 on said slats,which are rendered adjustable therein by means of thumb-screws 61. Theslats 58 being adjustable on the bar 58 independently of each other, itis obvious that the size of the openings leading from the air-trunk tothe several compartments may be regulated according to the condition ofthe material that is'to be cleaned. As the fine material onlyisseparated from the middlings in the upper part of the machine and as theair-current is somewhat stronger at that point, the upper slats of theseries will be adjusted to leave asmaller opening between the air-trunkand the compartments than at the lower part of the machine, where thecoarser heavier foreign material is removed from the middlings and theair-current is weaker. Instead of providing an airtrunk for each pair ofcompartments I may divide the trunks vertically, so-that there will Inthis case I provide a discharge-opening in the bottom of eachsubdivision of the air-trunks, so that the dust coming from eachcompartment will not be mingled with the dust from the othercompartments, as it frequently happens that the dust from onecompartment or section of the chamber is of better quality than fromanother.

In order that the operator may adjust the slats when the machine is inmotion, I prefer to provide a threaded bolt 62'at the upper end of thebar 58, said bolt extending up through the top of the casing and securedto a bracket 63 by-lock-nuts 64. In the bottom of each air-trunk Iprefer to provide discharge-openings 65, leading to spouts 66, throughwhich the heavier and coarser foreign material which will settle to thebottom of the airtrunk may be discharged outof the machine. The top ofeach air-trunk is provided with large openings 67, connected with theopenings 8 by flexible spout connection 68, and within these hoods orspout connections 68 I prefer to arrange rings or hoops 69 to preventthe fiexible connections 68 from contracting and shutting oif theair-currents.

Any suitable means may be provided for suspending the gyrating casingwithin the frameof the machine; but I prefer rods 70, secured at theirupper ends in the top of the frame and at their lower ends to lugs orbrackets 71, provided on the bottom of the casing. I have shown in Fig.1 but one feedspout for delivering material to the machine; but it willbe understood that I may provide an independent spout for eachcompartment, so that at any time the operator may feed different gradesof stock into the machine and clean them independently.

The operation of the machine is as follows: The operator having adjustedthe air-regulating devices within the air-trunks starts the machine andpermits the stock to flow into the receiving-chambers, from whence itwill be delivered in a'uniform sheet upon the outer ends of the sieves.The swinging or gyrating motion of the machine will advance the materialtoward the inner or tail end of each sieve, and the transverse stripswill prevent the material from dancing around on the sieve and will aidin advancing it toward the center of the machine. The air-current abovethe top sieves will be stronger than above the others, and consequentlythe upper air-regulating devices will be adjusted so that there will beless space or opening between the air-trunks and the spaces above thetop sieves. As the air-current grows weaker toward the bottom of themachine the lower air-regulating devices will be adjusted to leavelarger openings between the airtrunks and the compartments. At any timewhile the machine is in motion the operator may adjust the airregulatingdevices by .means of the bolt and lock-nuts on the top of the casing. Asthe machine is operated currents of air will be established through theopenings in the outer walls of the compartments, up through the sievesand the material thereon, through the air-trunks, and up o casing of thepurifier.

into the fan-casing. The dust and fine particles will be lifted out ofthe stock as it passes through the upper sieves and a large quantity ofit carried in suspension by the air-cur- 5 rent up to thedust-settlingchamber provided in the bottom of the fan-casing. In passing through theair-trunks the heavier particles will drop to the bottom and bedischarged through the openings therein. As the midro dlings pass downthrough the sieves the coarser particles, the bran, and fibers will beseparated from the pure stock and carried out into the air-trunks anddeposited on the bottoms thereof, while the purified stock will I 5 passthrough the lower sieves of the series and be discharged through theopenings in the bottoms of the compartments. A very complete separationof the middlings stock is thus efiected, and as many different gradesmay be cleaned at the same time as there are separate independentcompartments in the machine. The currents of air passing verticallythrough the compartments will serve to clean the meshes of the sieves ofdust or other foreign material that may lodge therein,

so that the sieves can be kept clean Without the necessity of removingthem from the machine. By providing the vertical air-cu rrent I am ableto use stationary sieves successfully and eflect a thorough separationof the middlings stock and at the same time prevent the sieves fromclogging.

I do not Wish to confine myself to the particular arrangement of thesieves in the com- 5 partments or the position of the perforated floorsand gathering-boards with respect thereto, nor to the particularconstruction of the receiving-chambers provided within the sieves, asthe same may, with other details of construction, be modifiedconsiderably by any one skilled in the art without departing from myinvention.

I have shown and described in this application certain parts of amiddlings-purifier that are also shown in an earlier application, filed5 5 Patent- 1. Amiddlings-purifier,comprisin g aswinging or gyratingcasing divided into aseries of compartments or chambers, a verticalseries of sieves horizontally arranged in said com- 6o partments andbetween which a vertical series of horizontal air-trunks are formed, ahorizontal series of vertical air-trunks provided between saidcompartments or chambers and communicating therewith, and

means for maintaining ascending currents of air through said sieves andthe material thereon and through said horizontal and verticalair-trunks, substantially as described.

2. A middlings-purifier,comprisingaswinging or gyrating casing dividedby partitions into compartments, sieves provided in said compartments,radial air-trunks provided between said compartments and communicatingtherewith, and means for maintaining ascending currents of air throughsaid compartments and said sieves and the material thereon and throughsaid radial air-trunks, substantially as described.

3. Amiddlings-purifier,comprisingaswinging or gyrating casing divided bypartitions into a series of independent compartments, stationary sievesprovided in said compartments, feed-spouts for delivering the materialto becleaned upon said sieves, radial airtrunks provided between thealternate pairs of compartments and communicating with said pairsrespectively, and means for main taining ascending currents of airthrough said compartments, through said sieves and the material thereon,and through said airtrunks, substantially as described.

4. A middlings-purifier, comprising a gyrating casing divided bypartitions into a series of compartments, sieves provided in saidcompartments, feed-spouts for delivering material to said sieves,air-trunks provided between said compartments and communicatingtherewith, a suction-fan and suitable air trunks. or passages connectingsaid fan with said air-trunks whereby currents of air will be maintainedthrough said compartments and said sieves, the material thereon andthrough said air-trunks, substantially as described.

5. Amiddlings-purifier,comprisingaswinging or gyratin g casing dividedby vertical partitions into a series of independent compartments,stationary sieves provided in said compartments, radial air trunksprovided between said sieves and communicating with said compartments,means for maintaining ascending currents of air through saidcompartments, said sieves and the material thereon and through saidair-trunks, and means provided in said air-trunks for regulating thecurrents of air above each sieve independently of the currents abovetheremaining sieves, substantially as described.

6. Amiddlings-purifier,comprisingaswinging or gyrating casing'divided byvertical partitions into a series of compartments, sieves providedWithin said compartments, radial air-trunks provided between saidcompartments and having openings in their walls communicating with thespaces above said sieves,

vertically-adjustable slats provided on the walls of said air-trunkswhereby the currents of air over said sieves may be regulated, and asuction-fan device connected with said airtrunks adapted to maintaincurrents of air through said compartments and said airtrunks,substantially as described.

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7. In a middlings-purifier, the combination,

with a gyrating casing divided by partitions into independentcompartments, stationary sieves provided within said compartments,radial air trunks provided between said sieves having openings in theirwalls, and communicating with the said compartments, means forregulating the currents of air through the openings in the walls of saidairtrunks, discharge-openings provided at the bottom of said air-trunks,and a suction-fan device connected with the tops of said airtrunks,substantially as described. Y 8. Inamiddlings-purifier,the combination,with a gyrating casing divided by partitions into independentcompartments, sieves provided within said compartments, radial airtrunksprovided between said compartments, said air-trunks having openings intheir walls communicating with the spaces above said sieves, bars 58'vertically adjustable on the walls of said air-trunks, the cross-slats58 adjnstably secured to said bars 58 and whereby the currents of airthrough the openings in the walls of said air-trunks may be regulated,and a suction-fan device connected with the tops of said air-trunks,substantially as described.

9. In a mid dlings-purifier,the combination, with a gyrating casingdivided by partitions .into compartments or chambers, stationary sievesarranged within said compartments, perforated plates or floors providedabove said sieves, spouts wherefrom the material is delivered to saidsieves, air-trunks provided between said compartments andhaving'openings in their walls communicating with the space above saidperforated floors, a suctionfan device connected with said air-trunksand adapted to establish ascending currents of air through said sieves,the material thereon and said floors and means for regulating thecurrents of air through the openings in-the walls of said air-trunks,substantially as described.

10. In a middlings-purifier, the combination, with a gyratin g casingdivided by partitions into compartments or chambers, stationary sievesarranged within said compartments, delivering-spouts provided above saidsieves, gathering-boards provided beneath said sieves to receive thematerial therefrom, air-inlet passages or ports provided in the walls ofsaid casing between said gatheringboards and said sieves, ascending-airtrunks provided between said compartments, said air-trunks havingopenings in their walls communicating with the space above said sieves,and a suction-fan device connected with said air-trunks and adapted tomaintain currents of air through said sieves and said compartments,substantially as described.

11. In a gyrating middlings-purifier, a sieve composed of a series ofstrips of suitable sieve material transversely arranged in thesieveframe, said strips gradually increasing in coarseness of mesh fromthe head toward the tail of the sieve, and narrow comparatively stifftapes or strips 37 provided between the edges of the abutting strips andextending above the surface of the sieve, whereby the material isadvanced toward the tail of the sieve by the motion of the machine.

12. A middlings purifier, comprising a swinging or gyrating casingdivided by partitions into a series of independent compartments orchambers, sieves provided in said compartments, air-trunks providedbetween said compartments or chambers and communicatingtherewith,dust-collecting chambers provided in the lower part of saidair-trunks and means for maintaining ascending currents of air throughsaid compartments and said sieves and the material thereon and throughsaid air-trunks, substantially as described.

13. A middlings purifier, comprising a swinging or gyrating casing, aseries of sieves provided one above the other therein, ascending-airtrunks provided between the sieveframes, the walls of said trunks havingopenings communicating with the spaces above and below said sieves, anda suction-fan connected with said air-trunks.

14. A middlings purifier, comprising a swinging or gyrating casingdivided into a sewith the spaces above and below said sieves,

and means connected with said air-trunks formaintainingascendingcurrents ofairthrough said sieves and the materialthereon, substantially as described.

15. A middlings-purifier, comprising a gyrating or swinging casing aseries of stationary sieves provided within said casing, ascending-airtrunks provided between and extending above and below the alternatepairs of sieves, the walls of said trunks having openings communicatingwith'the spaces between said-sieves, and a suction-fan device connectedwith said air-trunks and adapted to create ascending currents of airthrough said sieves and the material thereon, substantially asdescribed.

16. A middlings purifier, comprising a swinging or gyrating casing, aseries of sta- 17. A middlings-purifier, comprising a circular gyratingcasing, a series of sectorshaped sieves provided within said casing,ascending-air trunks provided between the alternate pairs of said sievesand having openings in their walls communicating with the spaces aboveand below the several sieves of the series, and a suction-fan deviceconnected with said air-trunks and adapted to create ascending currentsof air through said sieves and the material thereon, substantially asdescribed.

18. A middlings-purifier, comprising a circular gyrating casing, aseries of sieves arranged one above the other therein, ascending-airtrunks arranged between the sieveframes and having openings in theirwalls communicating with the spaces above and below the several sievesof the series, said trunks extending to the wall of the casing, wherebycurrents of air may be established transversely of said sieves, and asuctionfan connected with saidair-trunks.

19. In a middlings-purifier, the combination, with a gyrating casing, ofsieves arranged one above the other therein, receiving-chambers providedabove the outer ends of said sieves, said chambers having holes in theirfloors or bottoms through Which the material is fed in an even sheetupon the heads of the sieves, and feed-spouts between and alternatingwith said sieves and through which the material is conducted to saidchambers, substantially as described.

20. In a middlings-purifier, the combination, with a gyrating casing, ofa series of sieves arranged one above the other therein,receiving-chambers provided over the outer ends of said sieves andhaving dischargeopenings in their floors through which the material isdeposited in an even sheet upon said sieves, gathering-boards providedheneath said sieves, and feed-spouts leading from said gathering-boardsto said receivingchambers, substantially as described.

21. In a middlings-purifier, the combination, with a gyrating casing, ofa sieve arranged within the same, a receiving-chamber 41 provided overthe outer end of said sieve, said chamber having a series ofdischargeopenings 42 in its floor or bottom through which the materialis fed in an even sheet upon the head of the sieve, overflow-openings 43provided in the wall of said chamber through which the excess materialfed thereto is discharged upon said sieve, a feed-spout 43', and a spout46 connecting said spout 43 with a suitable delivery-pipe, substantiallyas described.

22. In a middlings-purifier, the combination, with a gyrating casing, ofa sieve arranged therein, a receiving-chamber provided over the outerend of said sieve and having holes in its bottom through which thematerial is fed in an even sheet upon the head of the sieve, afeed-spout 43 through which the material is fed to saidreceiving-chamber, a slotted plate 44 through which said feedspout43'extends, an air-trunk connected with the space above said slotted floor,and a suction-fan connected with said air-trunk.

23. In a gyratingmiddlings-purifier,a sieve, in combination with aseries of tapes arranged on edge transversely of said sieve and atintervals thereon, said tapes being inclined toward the tail of thesieve to aid in advancing the material over the same.

24. The combination,\vith agyratingcasing, of sieves arranged therein,radial air-trunks provided between the sieve-frames and extending to thewall of the casing and communicatin g with the spaces above and belowsaid sieves, a fan-casin g mounted on said gyrating casing, a fanprovided therein, and a dust collecting chamber in the lower part ofsaid fan-casing and communicating with said fan and with each of saidair-trunks, for the purpose specified.

25. A middlings-purifier, comprising a gy rating casing,a series ofsieves arranged therein, vertical air-trunks provided between thesieve-frames and having openings in their walls communicating with thespaces above and below the several sieves of the series, dust-collectingchambers provided at the bottoms of said air-trunks, suitable dischargespouts therefor, and a suction-fan device c011- nected with the tops ofsaid air-trunks and adapted to create currents of air through saidsieves and the material thereon, substantially as described.

26. A middlings purifier, comprising a swinging or gyrating casing, aseries of sieves provided one above the other therein, airtrunksprovided between the sieve-frames and having'openings in their wallscommunicating with the spaces above and below the several sieves of theseries, (lust-collecting chambers for the heavier refuse materialprovided in the bottoms of said air-trunks, and a suctionfan deviceconnected with the tops of said air-trunks and adapted to createcurrents of air through and across said sieves and through saidair-trunks to separate the lighter particles of dust from the middlings,substantially as described.

27. In agyrating middlings-purifier,a sieve, in combination,with aseries of tapes arranged transversely at intervals thereon, said tapesbeinginclined toward the tail of the sieve and adapted to yield to theweight or pressure of the advancing material, for the purpose specified.

28. In a gyrating middlings-purifier, a sieve composed of a series ofstrips of suitable sieve material, in combination, with tapes or strips37 provided between the edges of the sievestrips and extending above thesurface of the sieve and yieldingly inclined toward the tail of thesame, whereby the movement of the material is accelerated over thesurface of the sieve.

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a free gyrating movement permitted,substan- IO tially as described.

In witness whereof Ihave hereunto'set my hand this 18th day of June,1900.

GEORGE VALTER.

In presence of- W. W. REDMOND, P. G. WADHAM.

